| 摘要 |
PROBLEM TO BE SOLVED: To provide an antenna apparatus which reads information of a plurality of radio tags without mechanically moving an antenna, and suppresses the radiation of unnecessary radio wave, and also to provide an article management system. SOLUTION: Power is fed to one end of a linear conductive element 131 at a power feeding point 133 and the other end is connected to a ground plate 130 via a terminal end element 134. Each one end of branch conductor elements 132-1, 132-2, 132-3, 132-4, where an element length is one-fourth of a wave length, is connected to the linear conductive element 131, and the other end is short-circuited to the ground plate 130. Thus, connection points between the branch conductive elements 132-1, etc., and the linear conductive element 131 become high in impedance when viewing from the linear conductive element 131, so that the radio wave is not emitted from the branch conductive elements 132-1, etc. When the radio tag exists near the branch conductive elements 132-1, etc., electromagnetic field coupling occurs between the branch conductive elements 132-1, etc., and the radio tag, so that the radio wave is emitted from the branch conductive elements 132-1, etc. COPYRIGHT: (C)2008,JPO&INPIT |
